Yep, thats what I figured. How big a job is it? I dont think I want to try to tackle it myself, just trying to figure out how much I should expect to pay a plumber. Thanks

: The valve needs to be repaired.

: : I live in an apartment building and have a pressure valve toilet (the kind you find in office buildings, without a tank, I think this is what they are called). It has recently started running, with water continuously flushing, for anywhere from 5 minutes to an hour -- but only after about 11 pm; during the day it seems to be fine. Am I right in thinking this has to do with the water pressure in the building? Some pipes burst in the building on the floors below some weeks ago, right around when this started; could the repairs have affected the pressure? Or is it simply that the valve is wearing out? Any thoughts would be greatly appreciated.